Electrodepositing organic material such as rubber upon porous objects of nonconducting material such as fabrics



June 15 1926. 1,589,325

7 S. E. SHEPPARD ET AL ELECTR ODEPOSITING ORGANIC MATERIAL SUCH AS RUBBER UPON POROUS OBJECTS OF NONCONDUCTING -MATERIAL SUCH AS FABRICS Filed April 1. 1926 INVENTORS,

SamueLESheppard & Carl L. Beab, BY @PQW AT'TORNEYI Patented June 15, 1926.

UNITED STATES SAMUEL E. SHEPPARD Ann CARL L. BEAL,

EASTMAN KODAK COMPANY, 01? NEW YOR ELEoTRonErosITING ORGANIC MATERIAL.

0E RoonEsTER, NEW YORK. AssIoNoR's T0 ROCHESTER, NEW YORK, A CORPORATION OF SUCH AS RUBBER UPON POROUS OBJECTS 0F NONCONDUCTING MATERIAL SUCH AS FABRICS.

Application filed April 1,

This invention relates to processes of electrodepositing organic material, such as rubber, upon porous objects of non-conducting material, such as fabrics. One object of the invention is to' provide a process of this character in which the electrodeposition will be very accurately controlled. Another object of the invention is to provide such a process in which evenness of the deposit is insured. Still another object of the invention is to provide such a process in which certain steps predetermine the degree of penetration of the deposit into the porous material'or fabric. Another object of the invention is to provide good adhesion between the deposited substance and the material on which it is deposited. Other objects will hereinafter appear.

In the accompanying drawing the single figure is a diagrammatic sectional view of one form of apparatus in which our process may be carried out, the relative sizes of the parts being exaggerated for the sake of clearness. I

In U. S. Patent No. 1,476,374. Sheppard and Eberlin, December 1th, 1923, for electrodeposition of rubber coatings it is stated that the electrodeposition of rubber from emulsions thereof can be carried out upon porous non-conducting objects, such as wood, for example, by impregnating them with solutions of electrolytes. Thisprinciple is of general applicability to all porous objects of non-conducting materials, such as cloth and similar fabrics. A continuous method of electrodepositing organic materials from aqueous emulsions thereof onto fabrics is disclosed in co iiending application Serial No. 35,612, Sheppard and Eberlin, filed June 8th, 1925, for electrodeposition of rubber under gas-removing con ditions' v In the deposition of the minute particles of organic material, such as rubber, upon the fabric or other porous material, it is desirable to control the depth of penetra-. tion of the deposit into the pores. For example, it may be desirable to provide a de-, posit all the way through the fabric soas to thoroughly impregnate it with the coating substance, such as rubber. On the other hand it may be desirable at times to confine the deposit practically to one surface 1926. Serial No. 99,079.

of the fabric.-. For the production of certain water-proofed cloths the impregnation may be intermediate between the two extremes indicated above. Moreover, it may be useful to lightly waterproof the threads or fibers of the fabrimby effecting a light depositupon them.

W'e-have found that the depth and character of the deposit can be controlled by adding a size containing a coagulant to the porous object of non-conducting material, such as the fabric, before the electrodeposition takes place. In general we prefer to use acid hydrophil'ous colloids which are typified by such substances as glue, starch, dextrin', etc. In the preferred. form of our invention we use such'colloids having a p value greater than 3 and less than 7. Of course, the depth to which the size is forced into the fabric adds a feature of control in addition to the acid or coagulant mentioned above.

It is also highly desirable to provide. uniform deposits. Even where the size mentioned above is uniformly associated with the fabrio,'or other porous object, unevenness may occur through the uneven wetting ability of fibers in different parts of the fabric. This is due to the presence of antiwetting substances, such as grease, oil and the like. We have found it desirable, where such deleterious substances are present, to subject the fabric, or other porous object, to a treatment whichremoves the anti-wetting substances, such treatment comprising in the preferred form of our invention an immersion in an alkaline degreasing bath.

We shall now describe the preferred embodiment of our invention by way of illustration, but it will be understood that. our invention is not limited to the details thus given, except as indicated in the appended claims. Referring. to the accompanying drawing, the porous non-conducting material, say a cotton cloth, such as is commonly used'for the preparation of waterproof rubberized sheets, is unwound from roll 1 and passed througha bath 2 for removing antiwetting substances. It may be conveniently led beneath a roll 3 which keeps it properly immersed. At the top'of the tank are guide and squeezing rolls 4. In the tank any suitable bath may be employed. We have found loo that an alkaline degreasing bath is particularly effective, such as a aqueous solution of sodium sulfite. Of the great many useful alkalies that may be employed, we note also sodium carbonate, tri-sodium phosphate and sodium bisulfite. The excess of degreasing solption is squeezed out of-the fabric by the s4 and the fabric then passes through tanks 5 and 6 in rhich it is washed by water. Between each tank and the next are located additional guide and squeeze rolls 7 and 8.

'After having been freed from anti-wetting substances and having been thoroughlywashed, the cloth next passes into the bath 0E, or a 5 to 10% glue solution, or a .5 to 1% solution of agar-agar. The sizing material rial, and improves the smoothness of the enters into the pores'or openings in the fabno, or other porous non-conducting matecoating which is electrodeposited. These sizes may. be varied in acidity from almost neutral to say pI-I3, the most useful range being pH values greater than 3 and less than 7 The acids which we prefer to employ are the inexpensive and easily controlled organic ones, such as acetic, formic, oxalic or lactic. The initial acidity of the size assists reatly the striking or initial deposit of the particles from the emulsion uponthe fibers and in the pores of the fabric. This. is probably due to a slight coagulating effect. Moreover, the acid1ty of the size has the further advantage of preventing the rubberparticles from passing entirely through the fabric and onto the metal anode,

' which will be hereinafter described.

Where 0111 a light proofing is required, less concentr ted. and less viscous sizes than those just described above ma be employed. They'will be varied also wit the closeness of texture and thickness of the fabric,-as will 50 be understood by those skilled in the art.

Where it is desirable to impregnate the fab-' ric'with'the deposit only slightly on one side of it, a slightly'acid and rather viscous size is used, say one having a pI-Ivalueof 5'to 4.

The fabric is thoroughly impregnated with this Size and then electrodeposition carried onas hereinafter described, Besides controlling'thedegree of penetration of the coating a firm adhesion 'of the deposit to the fabric can be obtained.

Sometimes it is desirable to have the deposit extend thoroughly through the-fabric and on both faces thereof. In this case we:

use a size, the acidity of which is very slight Eber'lin, Serial ing agents therefor an under 7 but above 5. This size-is not worked into the fabric but is merely applied to the back of it (the side opposite the one from which theelectrodeposited particles come). This application is preferably made just prior to the electrodeposition process, so that there will be little, if any, chance for the size to soak into the fabric. "The mechanical expedients for coating one face of a fabric with a-viscous material, such as a size, are virlellknown and need not be described furt er.

For very light waterproofing or showerproofing, rubbermay be electrodeposited after a special adjustment of the size. The fabric is coated on the back with a thin size such, for example, as an aqueous solution containing from .1 to .3% agar-a ar and about-2% acetic acid. Wehave l' ewise found it'useful to modify the bath by addinga' small amount of a buffering electrolyte, such as sodium sulfite,say .3 to- .5%. With this sizing, properly applied, as specified above, there is obtained, upon electrodeposition, a soft even deposit which,

clear rubber coatin completel j wiaterproofing the cloth'wit out hiding its weave.

96 when dry, covers all the threads with a thin ionized neutral salts, oreven non-electrolytes, such as alcohol, which have a coagulating action u n the emulsion of rubber or other organic material.

The properly sized fabric next passes over the surface of an anode in the electroplatin'g bath of rubber emulsion, the. latter being indicated at 12 in the drawing. For such anode we prefer a rotary metallic drum 13. Suitable cooperating cathodes are shown at 14. In any event the sized fabric passes adjacent theanode in the path of the 4 current.

The bath from which the organic material is electrodeposited may be an aqueous emulsionv of the kind disclosed in the above cited Patent No. 1,476,374 or the one described in the-a plication of Sheppard and 0. 21,340, filed April 7th,

1925, for aqueous emulsion of unvulcanized rubber and sulfur. Other useful baths are disclosed, for instance, in a plication Serial No..21,342 Eberlin and Bea filed April 7th,

1925, for aqueous emulsions of electrodepositable cellulosic com ounds and coalescin application Se: rial No. 25,160 Sheppard and Beal, filed April 22nd, 1925, for electrodeposition of organic materials such asrubber and cellulosic compounds. The above mentioned baths are, of course, merely typical ones and any suitable aqueous emulsion containin organic material in the electrodepositab e state may be usedin connection with 4 .tially uniformly wettable,

the proper kind of porous object or fabric. See also application Serial No. 611,162 Sheppard and Eberlin, filed January 6th, 1923.

It will be noted that allof these baths contain not only the primary organic coating material but substances which assist the formation or perfection of the coating. For example, the deposition of the rubber includes the simultaneous passage of sulfur and other conditioning agents, such as accelerators and pigments into the deposit. This permits the rubber to be vulcanized in the exact place Where it is deposited in the porous object or fabric. Hereinafter when aqueous emulsions of rubber or organic coating materials are referred to, it will be understood that these terms include not only aqueous emulsions of rubber or such materials by themselves, but likewise and preferably emulsions in which the rubber or organlc material is associated with one or more conditioning agents which pass with it into the deposit.

Having thus described our invention,

what we claim as new and desire to secure by Letters Patent is:

1. The process of electrodepositing organic coating material upon porous objects of non-conducting material which comprises the stepsof adding to said objects a size containing a coagulant and bringing said sized object into contact with an aqueous electro-conducting emulsion of said organic coating material and passing an electrodepositing current through said emulsion with said object adjacent the anode in the path of the current.

2. The process of electrodepositin organic coating material upon porous o jects of non-conducting material which comprises the steps of removing anti-wetting substances from an object until it is substanadding to said object a size containing a coagulant, bringlnto contact with an organic coating material, and passing an electrodepositing current through said emulsion with said ob ect adjacent the anode in the path of the current. rocess of electrodepositm o r- 3. The ganic coating material upon porous o jects of non-conducting material which comprises the steps of treating an object with an alkaline degreasing compound, thereafter associating withsaid object a size containing a coagulant, bringing said sized object into contact with an aqueous elect-roconducting ing material and passing an electrodepositing current through said emulsion and ob- 'ect. J 4. The process of electrodepositing organic coating material upon porous objects of non-' which comprises the conducting material emulsion of said organic coatsteps of associating with an object a size comprising acid hydrophilous colloid, bringnon-conducting material which comprises the steps of removing anti-wetting substances from an object until the latter is substantially uniformly wettable, associatin with said object a size comprising an aci hydroph-ilous colloid, bringing said sized object into contact with an aqueous electroconducting emulsion of said organic coating material, and passing an electrodepositing current through said emulsion with said object in the path of the current to receive a deposit.

6. The process of electrodepositing rubber upon porous objects of non-conducting material which comprises the steps of associatin with an object a size containing an acid hydrophilous colloid, bringing said 'object into contact with an aqueous electroconducting rubber emulsion, and passing an electrodepositing current through said emulsion with said object adjacent the anode in the path of the current.

7. The process of electrodepositing rubber upon fabrics of non-conducting material which comprises associ ting with said fabric a size containing a hydrophilous colloid having. a pH value greater than 3 and less than 7 bringing said sized fabric into contact withan aqueous electroconductin emulsion of rubber and passing an electro epositing current through said emulsion with said fabric in a position to receive the resulting deposit.

8. The process of electrodepositing rubber upon fabrics of non-conducting material which comprises, removing anti-wetting substances from the fabric until it is substantially uniformly wettable, associating therewith a size containing a hydrophilous colloid having a pH value greater than 3 and less than 7, and bringing said sized fabric into contact with an aqueous electroconducting emulsion of rubber and passing an electrodepositing :current through said emulsion with said fabric adjacent the anode in the .path of the current.

9. The process of eleetrodepositing rubber upon fabrics" of non-conductmg material which comprises adding to said fabrics a size contammg a hydrophilous colloid havm a pH value greater than 3 and less than and bringing said sized fabric into contact with an aqueous electroconductingv emulsion of rubber and passin an electrodepositing current through said emulsion with said .fabric adjacent the anode in the path of the current, the extent towhich the size enters the fabric and the acidity'of the size being adjusted to control the penetration and character of the deposit.

10. The process of electrodepositing rubber upon cloth which comprises treating the cloth with an alkaline degreasing liquid, free- I ing it from said degreasing liquid, associating with it a sizing comprising a hydrophilous colloid. having a pH value greater than 3 and less than 7, bringing said sized cloth into .an aqueous electroconducting emulsion of rubber and passing an electrodepositing current through said emulsion with said current adjacent the anode in the path of the current.

Signed at Rochester,New York, this 26thday of March, 1926.

SAMUEL E. SHEPPARD. CARL L. BEAL. 

